The baby seal looked into the eyes of her executioner. Barely a flicker of emotion shows on the fisherman's face as he smashes a steel-tipped club into her mouth. She lay whimpering on the ice, blood pouring from her jaw and nose.

— Danny Penman, London Daily Mail, March 2008

For seven years I have witnessed this brutal scene as photographer for the International Fund for Animal Welfare (IFAW). I've been attacked, slipped into the frigid waters of the Gulf of St. Lawrence and dangled out of a helicopter in -30 degree F. weather. "How can you shoot that?" is the usual question from people. Even Dispatches editor Marianne Fulton expressed in an e-mail that she just couldn't look at any more pictures.

A young Harp Seal known as a 'beater' on the ice in the Gulf of St. Lawrence prior to the annual seal hunt. The Canadian government has set a quota of 275,000 seals to be killed for their fur. March 26, 2008.

It's a complicated subject that conjures different emotions from most people. To me it's become something dear to me that I can use my skills to help and at the end of the day I believe it to be a cruel hunt of a marine mammal, the Harp Seal, for a product no one needs – its fur.

It is also the most challenging job I do all year and a far cry from shooting the Academy Awards or David Beckham playing for the L.A. Galaxy, which is more like my everyday "meat and potatoes" work.

This year's assignment was to start with a glorious, pre-hunt, two-day shoot on the solid ice of the Gulf of St. Lawrence in Canada to try and get new footage of grey "beater" seals for IFAW's editorial and campaign purposes. I spent hours on my belly crawling around photographing inquisitive seals with beautiful and striking ice sculptures behind them under brilliant blue skies. The previous month's weather had bulldozed the ice pans together, forming enormous pressure ridges, some reaching six-seven feet high which I had to clamber over to discover the seals.

Each year we go through a complicated process with the Dept. of Fisheries to get a permit allowing us to "observe" the annual hunt. I undergo a criminal background check, pay for my observer permit and am interviewed and instructed on the rules of my permit. It states I must not interfere with either side of the hunt, seals or humans. The start date was announced quietly and we put in our applications. There were administrative delays though, so for the first day of the hunt we were without our permits. This would mean that even if the ice conditions were good enough, we would not be able to land or get close to the sealers. I was going to have to shoot from the helicopter, a minimum of 500 feet up and out.

A Ragged-Jacket Seal looks up at a hunter before it is killed in the 2004 Canadian seal hunt in the Gulf of St. Lawrence. Seal pups were slaughtered on the ice at the beginning of the hunt. A quota of 350,000 pups had been set. A seal may be legally killed as it loses it downy white fur at 12 weeks old. March 25, 2004.

Our spotter plane went ahead to look for the boats and shortly we received co-ordinates. As we neared under appropriately dull, grey skies, I saw four, six, eight small black dots on the horizon with one large one leading. The coast guard ice cutter drove through, smashing up the ice for the smaller fishing trawlers. "They're in transit," I said, watching the boats zigzag through the broken ice. In thick ice conditions the boats would land and sealers use snowmobiles and quads to move around collecting pelts in trailers but when the ice pans are small like this year they will often shoot the animals from the pitching bow of a boat. Men jump from ramps onto car-sized pans and club the seals, then drag them, not always dead, back onto the boat to skin them.

As we watched the boats push forward we spotted a few seals ahead of them. The ramp came down and I directed Martin, our pilot, to back up the helicopter, trying to keep pace with the boat. There was a tailwind and at maximum power the chopper was shimmying and juddering. I slid open my door and double-checked that my harness was clipped to the floor. The sealer ran down the ramp with his club, called a "hakapik," raised in the air. The seal began to scurry away but the hunter was too quick and his club came down on the animal's head. He clubbed again then hooked it and dragged it back, running to the boat. I followed the whole time and rolled the motor drive, a little nervous and conscious that these could be the only shots of the hunt today.

"There's another boat working ahead," said Martin, the seal unaware as it approached. Movement on the boat and the ramp is lowered. Again, the seal starts to slither away, moving surprisingly fast but not quick enough as the hunter's club strikes the side of its head.

My shutter speeds are very high, 1600th/sec, and I am worried about camera shake from the vibrating helicopter and gusting winds. I'm hand-holding a 500mm with 1.4 tele-converter on a Nikon D3. It's hard to hold it still on the frame with two moving subjects.

On this occasion the seal is not killed instantly and slips into the water but the sealer grabs and tries to lift its 50 lb. bulk. It slips away again but will surely die from its wounds. A victim of "struck and lost."

I take a second to check my monitor; the D3 is handling the huge contrasts and glaring ice exposures well. The white highlights are holding but it seems strange to worry about such things in the light of what I'm witnessing below. The cold is my biggest enemy today though. At -30 degree F. with the helicopter door open, my fingers are soon numb even with gloves on. I have to take my glasses off because when I breathe into my face mask they fog up. Soon my eyes are watering.

In the 2008 Canadian seal hunt, 275,000 seals will be slaughtered on the ice by clubbing. March 30, 2008.

Finally Martin, our pilot, says, "OK guys, time to go, and we've a decision to make." My head is buried under a coat, editing on my laptop. Through my headphones I hear him say, "The weather's looking bad and I'm worried about whiteout conditions over the ice. We could go to Sydney but we'll be stuck there when the weather moves in this afternoon." We had to get video footage back to Charlottetown on Prince Edward Island. "Well, we'll push on then but we may spend the night in the chopper on a beach," he said in that calm manner only pilots seem able to command.

I emerge from my coat and check the compass. We're headed SW and I need a SE view. We have a Hughes BGAN satellite phone about the size of a laptop and able to upstream at 126k, it's even wireless. Set up on the floor of the A-Star helicopter with a rough view of the horizon I get a signal and soon the pictures are being e-mailed to the office. I keep an eye on the transmit times and the other on the looming grey horizon merging with the ice. Eventually we spot PEI's windmills, a landmark for home.

Hovering into our hanger I gather my gear and as the rotors idle down we're greeted by Robbie Marsland, IFAW's seal campaign leader. "Nice job," he says, "the photos were up on the Daily Mail's Web site before you landed."

Some 270,000 seals were killed this year in the largest marine mammal hunt anywhere in the world.

Stewart Cook is a Los Angeles-based international photojournalist born and raised in England, specializing in photography that entertains and inspires – from the glittering world of Hollywood celebrities to endangered seals in Canada's northern reaches. Since 2001, Stewart has annually photographed the birth of Harp Seal pups on the ice floes of Canada's Gulf of St. Lawrence – and the highly controversial annual Canadian commercial seal hunt, in which hundreds of thousands of seals are hunted and slaughtered. The project has become one of his passions.

Stewart's work has been featured in some of the world's top publications including: The Times, Independent, Daily Mail, Daily Mirror, Telegraph, Guardian, People, Harper's Bazaar, Film, Marie Claire, GQ, In Touch, Allure, Us Weekly, Newsweek, Vanity Fair, Teen People, InStyle, Glamour, The New York Post, The Washington Post, Time magazine, Daily Express, Mail On Sunday, Sunday Mail, Saturday Times Magazine, OK, Hello, Now, and Maxim.